Every year, approximately half of Estonia is covered by flights, alternating between the northern and southern parts of the country, with larger settlements also being flown over every year.

Orthophotos are used for public services, forestry, agriculture, planning, and environmental protection (CIR false-color images to distinguish forest stands and tree species), among other things.

What equipment is used?

The flights are carried out with a Cessna Grand Caravan 208B (ES-MAA) aircraft, which will be equipped with the following from 2025:

• IGI UrbanMapper-2e – nadir+ oblique cameras (8x150MP RGBN), which enable general flights as well as 3D photo grid models focused on urban environments
• Laser scanner Riegl VQ-1460, which collects elevation data as point clouds
• PhaseOne iXM‑GS120 photo robot fotoladu.maaamet.ee for use – enables high-quality spatial data

All equipment purchased in 2025 is funded by the European Union.

How high are the flights and what is the resolution of the photos?

In densely populated areas (cities, small towns), aerial photos are taken with a GSD (ground sample distance) of ~4–10 cm, depending on the location:

• Separately flown settlements: 4 cm
• Spring mapping flights: 10 cm
• Summer forestry flights: 15 cm

Orthophotos can be downloaded as open data here.

In the case of laser scanning, the point density is up to 2/8/80 points/m², depending on summer/spring/settlements.

The point cloud from aerial laser scanning can be downloaded as open data here.

How is the orthophoto production process carried out?

1. Flight areas and product requirements are selected, flight paths and parameters are designed, and flight permits are coordinated.
2. Marking signs (60×60 cm white squares) are installed or reference points on the ground are measured, on the basis of which areotriangulation is later carried out.
3. Flights are carried out in suitable weather conditions.
4. Ground post-processing includes calculating flight trajectories, triangulation, improving elevation models, mosaicing, orthophoto harmonization, orthophoto compilation, cutting into map sheets, compilation of necessary photo formats, and addition to web services and other databases.
5. The result is accurate orthophotos (which can be used for measurements and geoinformation analysis) and elevation models.
6. The data will be published on the geoportal, photo store, 3D application, and WMS services starting in the fall.

Summary

Author: Mait Metsur, Advisor, Department of Geodesy and Aerial Surveying